"The white man by the door had to shift because the door would have hit him. When he shifted the door now fell on the floor of the plane," he said.

He added: "I wonder what would have happened if the door fell off midair."

Another passenger, Ola Orekunrin, told CNN she noticed the door had been "unstable" for the whole flight.

But Dana Air denied the door fell off as a result of a mechanical issue, and instead blamed "a passenger".

"We wish to state categorically that this could never have happened without a conscious effort by a passenger to open it," the Nigerian airline said in a statement.

The airline said when the aircraft was airborne, the door could not be "shaking" because it was "fully pressurised".

"A thorough inspection was however carried out on the said aircraft upon landing in Abuja by our engineers and a team from the Nigerian Civil Aviation Authority, and no issue was reported. There was also no threat to safety at any point."

"A thorough investigation of the concerned passenger is ongoing."

Nigeria does not have a strong aviation safety record. In 2012, a Dana Air flight crashed in Lagos, killing all 153 people on board.